Chemiresistive gas sensors based on LDH structure were investigated for the detection of widely used volatile organic compounds (VOCs) including methanol, ethanol, and acetone at room temperature. In order to increase the surface active sites and subsequently improve the detection sensitivity of gas molecules, the use of Ag decoration method along with the creation of porosity on the surface of LDH structures were investigated. In this method, methanol solvent was used as a hole scavenger and UV radiation as a catalyst for binding Ag to the surface of LDH sheets. The microstructure and morphology of the composites were investigated by FESEM, HRTEM, EDS, EDS mapping, XRD, and MS analysis. The investigated parameters included relative humidity, calibration curve, repeatability, selectivity, and response/recovery times. According to the obtained results, the creations of surface corrosion by methanol and decorating the structure with Ag have both affected the sensitivity of the sensors. The pure Ni-Al LDH sensor has a response value of 6.8–250 ppm of ethanol. By increasing the specific surface area and creating LDH nanosheets, the response value can be increased up to 8.52. Also, the addition of Ag NP (Ni-Al LDH decorated with Ag NP) has increased the response up to 10.89. It was also observed that the response times in different modes have the least difference. At the end, the response mechanism was investigated based on the heterojunction theory.

中文翻译：

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Ag纳米粒子修饰Ni-Al层状双氢氧化物作为气体传感器的研究

研究了基于LDH结构的化学电阻式气体传感器，用于在室温下检测广泛使用的挥发性有机化合物（VOC），包括甲醇、乙醇和丙酮。为了增加表面活性位点并随后提高气体分子的检测灵敏度，研究了使用Ag装饰方法以及在LDH结构表面创建孔隙率。在该方法中，甲醇溶剂用作空穴清除剂，紫外辐射用作催化剂，将 Ag 结合到 LDH 片表面。通过FESEM、HRTEM、EDS、EDS绘图、XRD和MS分析研究了复合材料的微观结构和形貌。研究的参数包括相对湿度、校准曲线、重复性、选择性和响应/恢复时间。根据所得结果，甲醇造成的表面腐蚀和Ag修饰结构均影响了传感器的灵敏度。纯 Ni-Al LDH 传感器的乙醇响应值为 6.8–250 ppm。通过增加比表面积并创建LDH纳米片，响应值可提高至8.52。此外，Ag NP（Ag NP 修饰的 Ni-Al LDH）的添加将响应提高至 10.89。还观察到不同模式下的响应时间差异最小。最后，基于异质结理论研究了响应机理。